Wheelchairs have long provided an efficient and practical means for mobilizing disabled individuals, particularly parapelgic individuals. The conventional or typical wheelchair in use at this time includes a seat assembly supported by a frame which in turn is supported by a pair of main rear wheels of usually relatively large diameter and a pair of caster-like front wheels of relatively small diameter. The main or rear wheels are independently mounted to enable a seated user to propel and maneuver the wheelchair with the arms and hands. While conventional wheelchairs of this nature have been found well suited for use in obstacle free environments, they have been found generally inadequate for use in natural surrounds, for example over rough or disintegrated surfaces.
In recognition of the limited usefulness of conventional wheelchairs efforts have been made to provide alternative designs which are capable of traversing common obstacles such as steps or stairs or rough terrain. For example, U.S. Pat. No. 2,751,027, U.S. Pat. No. 4,077,483 and U.S. Pat. No. 4,119,163 each disclose wheelchairs capable of traversing obstacles such as curbs. While each of the wheelchairs disclosed in said patents perhaps provide enhanced mobility for the user in certain situations, they are characterized by complex designs requiring a source of power other than that provided by the user. Accordingly, these wheelchairs are relatively heavy and cumbersome, so that they cannot be conveniently transported for example in the trunk of a car, and in addition have a limited range which makes then unsuitable for extended outdoor use. Moreover, the relative complexity of these wheelchairs makes them prohibitively expensive for many individuals.
As a need for an enhanced mobility user-propelled wheelchair of lightweight and uncomplicated design still exists, the present invention is provided. As will be seen from the ensuing drawing and description, the present invention fulfills a long felt need of parapelgic individuals for a practical and versatile wheelchair capable of extending their range of mobility into the natural environment.